Rear bumper for an automobile



FIG. 1 is a perspective view of a rear bumper of an automobile of our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof; and,

FIG. 6 is a right side elevational view thereof, the left side elevational view being a mirror image of FIG. 6. 

The ornamental design for a rear bumper of an automobile, as shown and described. 